What is an artificial reef?

An artificial reef is a manmade structure that may mimic some of the characteristics of a natural reef.

Can you spot the sunken ship?

In June 2002, the retired USS Spiegel Grove was sunk in waters off Key Largo. At 510 feet (155.45 meters) long, the ship was, at the time, the largest vessel ever intentionally scuttled for the purpose of creating an artificial reef.

Submerged shipwrecks are the most common form of artificial reef. Oil and gas platforms, bridges, lighthouses, and other offshore structures often function as artificial reefs. Marine resource managers also create artificial reefs in underwater areas that require a structure to enhance the habitat for reef organisms, including soft and stony corals and the fishes and invertebrates that live among them.

Materials used to construct artificial reefs have included rocks, cinder blocks, and even wood and old tires. Nowadays, several companies specialize in the design, manufacture, and deployment of long-lasting artificial reefs that are typically constructed of limestone, steel, and concrete.

A good view from inside the Thunderbolt.

In 1986, the Thunderbolt was intentionally sunk in 120 feet (36.6 meters) of water four miles south of Marathon and Key Colony Beach in Florida. The ship’s superstructure is now home to colorful sponges, corals, and hydroids, providing food and habitat for a variety of sea creatures.

The Florida Keys National Marine Sanctuary contains several decommissioned vessels that were sunk in specific areas for diving or fishing opportunities prior to the area’s designation as a national marine sanctuary. One of the most famous is the U.S. Coast Guard Cutter Duane, which served on the seas for half a century before its final assignment as an underwater haven for sea life.

Planned manmade reefs may provide local economic benefits because they attract fish to a known location and are therefore popular attractions for commercial and recreational fishermen, divers, and snorkelers. However, the increase in illegal dumping for the purpose of creating habitat has led to significant poaching in the Florida Keys and subsequent high-profile arrests by NOAA’s Office of Law Enforcement. Marine debris continues to be an ongoing problem in these sensitive environmental areas, and NOAA’s Marine Debris Program has helped provide funding to remove debris in the Florida Keys.